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Alexander Brinkmann

Publications and source records attributed to Alexander Brinkmann.

4 recordsLinked to original sources
PubMed2007

MR neurography with multiplanar reconstruction of 3D MRI datasets: an anatomical study and clinical applications.

INTRODUCTION: Extracranial MR neurography has so far mainly been used with 2D datasets. We investigated the use of 3D datasets for peripheral neurography of the sciatic nerve. METHODS: A total of 40 thighs (20 healthy volunteers) were examined with a coronally oriented magnetization-prepared rapid acquisition gradient echo sequence with isotropic voxels of 1 x 1 x 1 mm and a field of view of 500 mm. Anatomical landmarks were palpated and marked with MRI markers. After MR scanning, the sciatic nerve was identified by two readers independently in the resulting 3D dataset. RESULTS: In every volunteer, the sciatic nerve could be identified bilaterally over the whole length of the thigh, even in areas of close contact to isointense muscles. The landmark of the greater trochanter was falsely palpated by 2.2 cm, and the knee joint by 1 cm. The mean distance between the bifurcation of the sciatic nerve and the knee-joint gap was 6 cm (+/-1.8 cm). The mean results of the two readers differed by 1-6%. CONCLUSION: With the described method of MR neurography, the sciatic nerve was depicted reliably and objectively in great anatomical detail over the whole length of the thigh. Important anatomical information can be obtained. The clinical applications of MR neurography for the brachial plexus and lumbosacral plexus/sciatic nerve are discussed.

Adolescent↗
PubMed2003

Influence of Helicobacter pylori infection and omeprazole treatment on gastric regional CO2.

BACKGROUND: Gastric regional CO(2) accumulation indicates gastric mucosal hypoperfusion in critically ill patients. CO(2) is also a reaction product of urea degradation, and we therefore tested the hypothesis if regional pCO(2) is influenced by Helicobacter pylori infection. MATERIAL: Seven H. pylori-positive and 7 H. pylori-negative volunteers (age range 21-30 years) were investigated. During a 6- to 7-hour observation period, we obtained every 30 min arterial blood gases, gastric juice pH from a glass pH electrode and regional pCO2 from a gastric tonometer. The study protocol included subsequent periods of baseline measurements, pentagastrin stimulation (0.6 microg/kg/h/i.v.) and application of omeprazole (40 mg i.v.). RESULTS: Gastric regional pCO(2) was increased in H. pylori-positive versus H. pylori-negative subjects before (64.4 +/- 3.1 vs. 50.0 +/- 2.9 mm Hg, p < 0.005) but not after application of omeprazole. The effect of omeprazole on gastric juice pH was increased in H. pylori-positive subjects (mean pH during 4 h 6.1 +/- 0.3 in H. pylori-positive vs. 2.5 +/- 0.2 in H. pylori-negative subjects; p < 0.0001). There was a difference in arterial pCO(2) between H. pylori-positive and H. pylori- negative subjects (43.1 +/- 0.3 versus 38.9 +/- 0.3 mm Hg; p < 0.0001). CONCLUSION: H. pylori infection has a significant effect on gastric regional CO(2) that is suppressed by application of a proton pump inhibitor.

Adult↗
PubMed2002

Metabolic effects of norepinephrine and dobutamine in healthy volunteers.

The objective of the present study was to evaluate the effects of norepinephrine (n = 9) and dobutamine (n = 7) on carbohydrate and protein metabolism in healthy volunteers in comparison with a control group (n = 9). Norepinephrine (0.1 microg/kg min), dobutamine (5 microg/kg min), or placebo was infused for 240 min. The plasma concentration of glucose, lactate, epinephrine, norepinephrine, insulin, and glucagon were determined. Glucose and urea production and leucine flux were measured using a tracer technique. Norepinephrine caused a persisting rise in plasma glucose concentration, whereas the increase in glucose production was only transient. A minor increase in plasma lactate concentration was observed, but it did not exceed the physiological range. No change in leucine flux, urea production, or plasma concentration of insulin, glucagon, or epinephrine was found. Dobutamine slightly decreased glucose production, whereas the plasma concentration of glucose and lactate did not change. The reduction in leucine flux was paralleled by a decrease in urea production. No change in the plasma concentration of insulin, glucagon, or the catecholamines was observed. In conclusion, both norepinephrine and dobutamine have only minor metabolic effects. Because glucose production is enhanced by alpha1- and beta2-adrenoceptor stimulation, we conclude that dobutamine is only a weak agonist at these adrenoceptors. These minor metabolic actions may make both compounds suitable for critically ill patients because no further increase in metabolic rate should be caused.

Adrenergic alpha-Agonists↗